Data recovery of a RAID 1 ALLNet ALL6600 Thecus N5200 PRO NAS

The data recovery of the *.vmdk files were handled in our Business Service – The procedure was finished after two working days.

30. 5 2018 - Sebastian Evers

Initial data loss situation:

Storage media with data loss:

• ALLNet ALL6600 NAS (identical in construction to Thecus N5200 PRO NAS)
• RAID 1 (Mirroring)
• Two 2 TB hard disks (Western Digital WD20EFRX-68EUZN0)
• Several iSCSI volumes (fixed capacity) with VMWare / VMFS
• Virtual machines with dynamic capacity (*.vmdk) / NTFS
  

Data specified for recovery:

• Virtual server / File server
  

After a power blackout an important server within the storage area network of a churchly company failed. An iSCSI target containing a VMFS volume was not accessible via hypervisor (VMWare ESXi) and the availability was displayed with 0%. The ALLNet ALL6600 NAS and the ESXi were both rebooted, with the same result. Both hard disks were checked for damages, but appeared to be faultless. As with a previous data loss, Attingo was contacted once more.   

Analysis and conduction of the data rescue:

The physical analysis in the Attingo cleanroom laboratory showed that both hard disks had no physical damagesa and 100% raw data of both disks could be copied. The logical analysis revealed that the RAID 1 was degraded for a long time and the data of both disks was not in sync. The technician was able to access the VMFS volume of the more up-to-date disk and extract both important *.vmdk files. As requested the virtual machines were converted onto two separate physical storage media and delivered to the customer, who copied them back onto a newly created RAID system.